The present invention relates to liquid crystal devices, more particularly to liquid crystal devices having a pair of electrodes between which a liquid crystal layer is disposed.
Heretofore, liquid crystal devices have been employed for displays of microcomputers, word processors and compact televisions. Such a display is economical because of its small electricity consumption and suitable for compact apparatus.
FIG. 1 is a cross section view of a prior art liquid crystal device. The liquid crystal device comprises a pair of glass substrates 1 and 1' with polarizing plates 5 and 5' on the outsides of the pair of the substrate, a plurality of pairs of transparent electrodes 2 and 2' between which pixels are defined, oriented films 3 and 3' formed on the opposed inner surfaces of the substrates 1 and 1' and a liquid crystal layer disposed between the substrates.
To save the amount of the expensive liquid crystal necessary to form the liquid crystal layer, realize quick response of the device and make the device thin, the distant between the substrates is chosen narrow, e.g., about 1 to 20 microns. Because of such thin structure, when the substrates are assembled, a convex portion of the inner surface of one substrate with the height greater than the distant between the substrates could touch its counterpart surface and give rise to a short current path between the electrodes. As a result, such a liquid crystal device can not function normally. The substrates, therefore, have to be polished to make the opposed inners surface even. However, if flaws are inadvertently given to the substrate during assembling, the assembled device might have short current paths. Even if the height of a convex portion is less than the distance between the substrates, the transparent electrode 2 or 2' is particularly grown with the convex portion as a core during deposition of this, and and therefore is in contact with the opposite inner surface might happen.
The tolerable difference in distance between the opposed surfaces contiguously to a liquid crystal layer is about 2 to 3 microns, preferably the difference is less than 0.3 micron, when the liquid crystal device is 10 cm long by 10 cm wide.